uClibc

File: canonicalize.c line number 36

According to the documentation of realpath() the output buffer needs to be at least of size PATH_MAX specifying output buffers large enough to handle the maximum-size possible result from path manipulation functions. (In that instance, buf's size comes from uv__fs_pathmax_size(). That function attempts to use pathconf(path, _PC_PATH_MAX) as noted in the realpath(3) docs)

But over here uv__fs_pathmax_size() nor pathconf(path, _PC_PATH_MAX) is used.

Passing an inadequately-sized output buffer to a path manipulation function can result in a buffer overflow. Such functions include realpath() readlink() PathAppend() and others.